LAUSR

INTRODUCTION Langerhans Cell Histiocytosis is an orphan disease of clonal dendritic cells that affect the facial skeleton in majority of cases. Actual management for unique and small lesion with easy access is surgical resection. Biggest lesion, with surgical risk is treated by association of vinblastine and corticotherapy. There is no case reported of corticotherapy as neoadjuvant treatment before the surgery for Langerhans Cell disease. OBSERVATION In this case, a man age of 18 presented a unifocal frontal bone injury, occasioning pain and skin inflammation in front of orbital lateral superior wall. The CT scan showed an important inflammation of soft tissues, and a heterogeneous osteolysis of the right frontal bone in contact with dura mater. A short corticotherapy was administered followed by a surgical curettage, with parietal bone graft reconstruction. During surgery, soft tissue inflammation wasn't found, and dura matter wasn't invaded. Histological examination confirmed the diagnostic of Histiocytosis. The treatment allowed symptoms resolve. CONCLUSION This case shows that corticotherapy doesn't negative histological examination in Langerhans Cell Histiocytosis and could facilitate its dissection and resection.